Again (as in 1 Corinthians 7:29b), Paul’s instructions should not be understood too literally. He is not advocating a stoic life, devoid of feelings and desires. Rather, he is reminding the Corinthians that the sorrows, joys, and possessions of this world are not of ultimate concern.
30 and those who mourn as though they were not mourning, and those who rejoice as though they were not rejoicing, and those who buy as though they had no goods,